The Lebanese army said its troops killed six Islamist militants and arrested 16 others near the Syrian border on Wednesday, in its largest operation against the Islamic State group.
The soldiers launched the raid, in which local IS group chief Anas Zaarour was killed, at dawn in the Arsal region of eastern Lebanon, a military spokesman said.
A "most wanted" militant, Ahmad Noun, was among those arrested.
"It was our largest operation against Daesh... in terms of size and the number of people killed and captured," the spokesman told AFP, using an Arabic acronym for IS.
The army said in a statement that its "lightning" raid was launched on the basis of information that the Islamist militants were planning attacks on military posts and to kidnap civilians in Arsal.
In August 2014, the army clashed with Islamist militants of IS and Al-Nusra Front, Al-Qaeda's affiliate in Syria, in the Arsal region, with militants kidnapping 30 Lebanese soldiers and policemen as they withdrew back along the border.
After long and arduous negotiations, 16 of the kidnapped men were released at the start of December in exchange for Islamist prisoners held in Lebanese jail.
The jihadists executed four of their hostages while a fifth died of wounds he suffered in the initial Arsal clashes, leaving nine members of Lebanon's security forces still in their hands.
Both the Lebanese army and the Shia militant group Hezbollah has since 2014 carried out attacks in the Bekaa region of eastern Lebanon on Syria-based Islamist militants.